Given the growing popularity of digital entertainment and services, such as digital cable television (CATV), video on demand (VoD), voice over Internet protocol (VoIP), high-speed Internet access, etc., various techniques have been implemented in broadband networks for delivering information to users. Many broadband networks use quadrature amplitude modulation (QAM) to deliver digital information to users. Typically, QAM transmitters are used to maximize the amount of information that may be transmitted to users via the network.
These transmitters require highly linear components to meet the channel transmission standards set forth by Data Over Cable Service Interface Specification (DOCSIS) or some other transmission specification being adhered to. In many instances, power amplifiers with high dissipation must be used to prevent harmonic distortion products which fall in-band and to prevent spectral spreading that can affect adjacent channels. These high dissipation amplifiers create a large amount of heat and are physically large, and both of these factors limit the maximum number of transmitters per board and per chassis. This decreases the channel density that can be provided and drives equipment costs up.
Furthermore, it is becoming more and more popular for content and service providers to make an increased amount of content available on-demand via broadband networks to users. To accommodate such trends, the broadband network infrastructure for delivering the programming, such as QAM transmitters, must be increased and may be provided at nodes closer to the user to provide these services without delay or other quality degradation. However, as described above, the high dissipation amplifiers conventionally used in transmitters produce a large amount of heat and are physically large. These factors limit the maximum number of transmitters that may be provided per board and per chassis, and can drive costs up, especially, when service providers may be increasing the number of transmitters being used to provide VoD and other services.